Cook your bacon until nice and crispy. Set aside on paper towels. Assemble your sandwiches by first spreading a thin layer of butter on one side of each piece of bread for the sandwich. Then layer on two slices of cheddar on one peice of bread (on the unbuttered side), then one slice of jack cheese, then a few slices of the sliced avocado then top with a few pieces of crisp bacon. Top that with 2 more slices of cheddar and top with bread (unbuttered side). Place buttered side of bread on to heat skillet. Cover with a lid to help melt cheese. Check after a few minutes and flip sandwich to other side once it starts to turn golden brown. Turn and cook on other side (with buttered side of bread facing down). Cook for a few more minutes with lid on to melt cheese. Once both sides are golden brown, remove from skillet. Slice sandwich in half and EnJOY!